Apoptotic/mytogenic pathways during human heart development

Objective: The aim of our study was to assess myocytes apoptosis/mitosis and associated intracellular signalling pathways during heart development. Setting and patients: Eight human fetal hearts (at different gestation ages) and seven human adult hearts were chosen as controls (five normal and two pathological) and studied from both a histological and a molecular point of view. Results: Our results are as follows: (i) all Shc isoforms are expressed and activated in the human fetal heart; (ii) a progressive fading of Shc and ERK expression are evident during gestation; (iii) JNK is present but it is not activated in the human fetal heart; (iv) CD95 is present in the first week of gestation and fades progressively; (v) apoptotic/proliferative processes are present in the early gestation phase and fades progressively; (vi) in the human heart, Shc isoform with medium weight is 55 kD and not 52 kD and it is upregulated in adult myocardial ischaemia. Conclusions: Myocyte underwent apoptosis/mitosis during gestation. Shc isoforms, together with ERK maintain the homeostasis of the heart.